Most UAE residents are vitamin D deficient: Can you just take supplements without a test?

Dubai: The UAE has sunshine almost every day of the year, and yet somewhere between 60 and 90 per cent of GCC residents are vitamin D deficient. So if the odds are that high, why not skip the whole doctor's visit and just buy a supplement from the pharmacy shelf?

It is a reasonable question. The answer, according to the doctors, is more complicated and one that suggests not to.

Why almost everyone here is at risk

"The paradox resolves once you separate sunlight being available from sunlight actually reaching the skin," says Dr. Anna Protasova, Specialist Dermatologist at Tajmeel Clinic in Dubai.

From roughly May to September, nobody is voluntarily outdoors between ten and four, which is exactly the window that drives vitamin D synthesis. Add clothing coverage, higher melanin skin tones that need longer exposure, sunscreen use, indoor jobs and diets low in vitamin D, and the deficiency rate stops being a surprise.

"Summer heat and temperatures above 40 degrees forces people to stay indoors," says Dr. Slavica Vukovic, Specialist Internal Medicine at RAK Hospital. "Traditional clothes in this region leave minimal skin exposed, and we advise patients to use sun protection creams before going outdoors, which is one more reason affecting vitamin D levels."

The at-risk list is broad: office workers who commute by car and park underground, shift workers, teenagers glued to screens, older adults, pregnant and breastfeeding women, breastfed infants, and people with obesity or a history of bariatric surgery. In other words, most of the population.

So can you just use supplement?

This is where the doctors push back, and the reason is chemistry.

"Vitamin D is not like vitamin C, where sufficient amounts are eliminated by the kidneys through urine," says Dr. Vukovic. "It is liposoluble, which means it could cause hypervitaminosis, even toxic effects, with amounts deposited in fat tissue and the liver."

That storage problem is exactly why more is not better. Walk into any UAE pharmacy and you will find everything from 400 IU to 50,000 IU sitting side by side, and to a shopper they look identical.

"The high-strength weekly capsules are designed to correct a documented deficiency over a defined period and then stop," says Dr. Protasova. "Taken indefinitely without review, that is where trouble starts." Sustained excess raises blood calcium, which can cause nausea, excessive thirst, frequent urination, constipation, confusion and, over time, kidney stones or impaired kidney function.

Dr. Job Simon, Consultant Endocrinologist at Burjeel Hospital Abu Dhabi, is the most specific. "A daily dose of 800 IU is sufficient to ensure adequate vitamin D levels. Higher doses taken over a prolonged period can lead to vitamin D toxicity."

Some people should not self-prescribe even ordinary doses, including anyone with kidney disease, parathyroid conditions or sarcoidosis, or those on certain diuretics and cardiac medications.

The test comes first

All four doctors agree that a simple blood test should come before any supplement. The correct one is serum 25-hydroxyvitamin D, which measures your actual storage levels.

"Waiting for symptoms is a weak strategy," says Dr. Protasova, "because fatigue, diffuse aching and low mood overlap with a dozen other things, and plenty of deficient people feel entirely fine." Her position for this region is: the test is cheap and the odds of deficiency are high, so anyone in a risk group should test regardless of symptoms.

And if you have been taking it for years?

"Get the test, and I would say it without alarm," says Dr. Protasova. "Two years of a low or moderate daily dose is very unlikely to have harmed you. But you have been treating something you were never confirmed to have, and you have no idea whether it worked."

Plenty of people supplement faithfully and stay deficient because the dose is wrong for their body weight, or because they take it without food, when it absorbs far better with a fat-containing meal.

As Dr. Radha Nilesh Patil, Specialist Dermatologist at Medcare Royal Speciality Hospital, says: "Supplements should not become something we take indefinitely simply because they are considered harmless. Vitamin D is essential, but supplementation should be individualised rather than based on the assumption that everyone needs a high dose."

So yes, you are probably deficient. No, that is not a reason to skip the test.